This invention relates generally to chair-control mechanisms, and more particularly to a mechanism that allows the horizontal fore-to-aft position of a chair seat to be adjusted relative to the seat back thereof.
Typical office chairs and the like are generally provided with an adjustment mechanism for permitting horizontal fore-to-aft adjustment of a seat. Some mechanisms are self-adjusting when the user shifts his or her weight. These designs contain detent and notch arrangements that prevent movement when the user is seated and allow movement when the user removes his or her weight from the seat. These configurations suffer from a number of drawbacks. For instance, the user must stand to adjust the seat. Further, chairs having this arrangement permit a substantial amount of side-to-side movement.
Another type of mechanism generally includes guide channels or tracks attached to the seat or base. The channels or tracks contain bearing members, such as depending rods or runners, that permit horizontal fore-to-aft movement of the seat relative to the seat back. However, these mechanisms are often bulky and increase the overall height of the seat such that it cannot be adjusted low enough to the ground to accommodate those in the lower height percentiles of the population. Accordingly, there remains a need in the adjustable chair industry for a horizontal adjustment mechanism which is relatively simple and inexpensive to manufacture and assemble and that only minimally changes the height of the chair seat.
Thus, while horizontal fore-to-aft adjustment mechanisms are known in art, it would be desirable to provide an adjustment mechanism for a chair, wherein the mechanism can be employed between a conventional seat and a tilt control mechanism that has a relatively low profile which does not significantly increase the overall height of the seat relative to the ground.